Haben Sie vielleicht einen Eimer Wasser für mich? Ich habe einen Platten.

What does a bucket of water have to do with a flat tire…or is this perhaps an interesting Redewendung?

A bucket of water helps you to finding the leak in the tube. You will see bubbles if you push the tube into the water. Of course, most cars and motorcycles have tubless tires. But most bikes still have tubes.